Artificial limb.



PATENTED AUG. 20, 1907.

T. S. SANDBBRG. ARTIFICIAL LIMB.

'APPLICIATIOI 21mm JUNE 20. 1906.

UNITED STATES PATENT OFFTQE.

ARTIFICIAL LIMB.

Specification of Letters Patent.

Patented Aug. 20, 1907.

Application filed June 20,1906. Serial No. 322,647.

To all whom it may concern:

Be it known that I, THEODORE S. SANDBERG, a citizen of the United States of America, and a resident of the city of Seattle, in the county of King and State of Washington, have invented certain new and useful Improvements in Artificial Limbs, of which the following is a specification. Y

My invention has special reference to artificial legs, and the primary object thereof is to provide a simplified and improved appliance of this nature.

With the above and other objects in view, to be referred to in the following, the invention resides in the construction, combinations and arrangement of parts as set forth in this specification and defined in the appended claims.

In the accompanying drawing, wherein like numerals of reference designate corresponding parts throughout the several views, Figure 1 is a vertical section of a por tion of an artificial leg embodying my invention, the said section being taken transversely of the ankle joint. Fig. 2 is a vertical section of same, taken on line 22 of Fig. 1. Fig. 3 is a plan view of the foot section detached. Fig. 4 is a view of the ankle part viewed from its lower end, and Fig. 5 is a transverse section taken on line 5-5 of Fig. 1.

With reference to the drawing, numerals 1 and 2 designate respectively the foot section and ankle part of the leg, and 3 indicates the ankle joint connecting said parts. The ankle part 2 is formed with an upwardly extending heel-like portion or shin part 3 and in conjunction therewith forms the lower leg section, the said parts being conveniently formed of wood with the grain or layers extending vertically. The ankle part is reinforced by member 2 in the form of a screw threaded rod, seated in a correspondingly screwthreaded hole extending through said ankle part transversely of the grain. The screw threads on said member and ankle part comprehend shoulders which stand in interlocking relation and insure the ankle part from splitting.

As will be observed upon reference to Figs. 1 and 5, the front portion 3 of the wall of shin part 3 increases in thickness downwardly throughout its base part, which is considerably thicker than the corresponding part of the rear portion of said wall. By this construction the shin part can be of comparatively light weight without sacrificing its strength, as the strain on said part when the leg is in use is mainly imposed on the front or thick portion of the wall.

The foot 1 comprises an upper portion, a5 4, conveniently formed of wood, and a flexible lower portion, as 5 preferably formed of hard felt which is secured to the wood part by cement. Extending across the upper face of portion 5 beneath the instep part of portion 4, is a body 10 of yielding resilient material, such as pure gum rubber, which projects forwardly of said instep part with its forward edge beveled in conformity with the outer surfaces of said portions. The forward portion of body 10 is left unconfined at its outer margin so as to permit of its yielding more readily when pressure is imposed on the toe portion of the foot in stepping.

Reference numeral 6 indicates an elastic member conveniently consisting of a section of suitable rubber extending across the bottom surface of the forward part of portion 5 and stretched longitudinally thereof, the said member being secured at its rear and front ends respectively to portion 5 by screws 7 and a stitching 7. Thus, the member 6 will have a constant tendency to draw the toe part of the foot-downwardly and imparts thereto a degree of elasticity which gives a more natural action to the forward portion of the foot in stepping and a forward impetus to the body of the wearer.

Beneath the heel part of foot 1 is a cushion 8, consisting of a body of pure gum rubber, which is secured to a facing 8 of leather fastened to said part, the said cushion having its under surface protected by a leather sole piece 9 which is secured to the rear portion of the foot and extends forwardly beneath member 6 but being unsecured thereto.

The foot 1 is formed with a flange 10 at the instep which projects upwardly and extends about the forward portion of the ankle part 2, and said ankle part is provided at its rear portion with a downwardly projecting flange 11 which extends about the upper part of the heel portion of the foot and serves to keep dust from entering between the rear portions of the foot and ankle parts and reaching the ankle joint.

As will be observed upon reference to Fig. 1, the upper surface 1 of the foot is inclined upwardly from the base of flange 10 in a rearward direction and the lower end surface of the ankle part is inclined upwardly in both a forward and rearward direction from the ankle joint 3, the rear portion of said end surface having a greater inclination than the forward portion thereof.

Disposed between the foot and ankle part, at the front and rear sides respectively of the ankle joint 3 are resilient members or cushions 12 and 14 consisting of blocks of pure gum rubber. Member 12 fits snugly within the flange 10 and is provided on its upper surface with a protective covering 12 of durable material, as leather, which has bearing against the opposing surface of the ankle part. The member 14 is preferably of elongated form and is seated endwise in a suitable recess 14 of the foot 1 with its upper end impinging the opposing surface of the ankle part, the said recess being inclined rearwardly in a downward direction and having its rear wall flared at the upper end so as to permit of a rearward compression of the upper portion of said member when the foot is planted on the heel, as in stepping forward, thereby bringing the forward portion of the foot closer to the ground.

Members 12 and 14 serve to absorb the shock attending the grounding of the foot, and in addition thereto, member 14 tends to give a forward impetus to the body of the wearer as the toe portion of the foot comes to the ground, and furthermore, returns the foot to its normal position relatively to the ankle part, as the weight of the body is removed from the foot preparatory to moving it forward, thereby permitting the wearer to swing the leg forward in a natural manner. a

The ankle joint 3 includes a tubular casing 15, seated in a suitable groove extending transversely of the lower surface of the ankle part 2, the said casing having upwardly projecting stems 16 in the form of stud bolts each of which has screw threaded connection with the wall of the casing at diametrically opposite points so as to efiect a rigid juncture. These stems extend through suitable apertures in the ankle part and are engaged at their ends by collar nuts 16 which impinge the upper end surface of said part. The casing 15 has suitable grooves 15 extending circumferentially in the periphery and is provided at each end with a removable cap, as 17, having screw thread ed engagement with its respective end portion of the casing. These caps are formed with shoulders 17 which project laterally from the periphery of the casingand embrace the foot 1.

Fitting snugly but rotatably in casing 15 is a pintle 18 having a stem 18, in the'form of a stud bolt which projects downwardly through a circumferential slot 19 in said casing, and through a suitable aperture in foot 1. This aperture terminates at its lower end, in a counterbore 19 in which is a collar nut 20 having screw threaded connection with said stem, whereby the foot can be readily detached from the ankle part by unscrewing said nut.

- Reference numeral 21 designates a bearing for casing 15, consisting of a semi-circular section of suitable yielding material, as leather, conveniently secured in a groove extending transversely of the upper surface of foot 1. By reason of its yielding nature, this bearing serves, in a marked degree, to absorb the shock on the ankle joint attending the grounding of the foot.

Furthermore, as the foot is used, ridges as 21, see Fig. 3, will be formed on the bearing in opposition to the grooves 15 of the casing and engage therein, thus, preventing lateral movement of the ankle part and foot relatively to each other, when grit entering back of the shoulders 17 has worn away the surfaces opposing said shoulders.

The casing 15 in connection with the caps 17, forms chambers at opposite ends of pintle 18, in which supplies of vaseline can be readily placed as desired, to keep the ankle joint lubricated, the lubricant in said chambers spreading between the pintle 18 and the casing and thence through slot 19, between the casing and bearing 21, during working of the joint.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. An artificial foot section comprising an upper portion of unyielding material, a base portion of flexible material projecting forwardly thereof and secured thereto, and a body of yielding resilient material extending substantially horizontally across the upper face of said base portion be neath the instep part of said upper portion and projecting forwardly thereof with its forward upper edge portion extending upwardly about the forward lower edge portion of said upper portion of the foot section, the forward end portion of said body being unconfined and beveled in con formity with the outer surfaces of said upper and base portions of the foot section.

2. An artificial leg comprising ankle and foot parts, a hollow casing arranged between said parts and secured to one thereof, said casing being formed with a circumtcrea tial slot and having open ends, a pintle mounted for rotation in said casing, a bolt secured to said pintle projecting through the slot of the casing and being secured in the other part, the ends of the pintle being spaced from the ends of the casing, whereby chambers for a lubricant are provided, and removable closures for the ends of said casing having laterally projecting shoulders embracing said ankle and foot parts.

Signed at Seattle, Washington this 14th day of .Tune 1906.

THEODORE S. SANDBERG.

Witnesses '1. II. SHELLEY, SAM H. Funnnn. 

